Refrigerating apparatus



Oct. 5, 1937. i L. A. PHILIPP 2,095,011

REFRIGERATING' APPARATUS I Filed MarchZZ, 1933 ATTORNEY.

Patented Oct. 5 1937 {PATENT o F -cE 2,095,011 BEFRIGERATING APPARATUSLawrence A. Phiiipp, Detroit, Mich, assignor, by

mesne assignments, to Nash-'Keivinator Corporation, Detroit, Mich, acorporation of Maryland Application March 22, 1933, Serial No. 662,057

8 Claims. (01. 62-115) This invention relates to refrigeratingapparatus, and more particularly to refrigerating apparatus of themultiple temperature type.

One of the objects of my invention is to prov vide an improvedrefrigerating system for freezing substances and for cooling circulatingair in a refrigerator cabinet.

Another object of myinvention is to provide a simplified arrangement forattaining a tem- 10 perature differential between a number of differentrefrigerant evaporators in a refrigerating system.

Another object of my invention is to provide an improved refrigeratingsystem and controls therefor for maintaining different temperatureswithin predetermined ranges in different parts of a refrigeratorcabinet.

Another object of my invention is to-provide within a refrigeratorcabinet an improved ar- 2 rangement of and control for refrigerantevaporating means, which is arranged and operated without the collectionof frost thereon or a slight film of frost is allowed to collect thereonduring the onphase of the refrigerating. cycle and is 25 melted offduring the off-phase of the refrigerating cycle, while at the same timeprovisions are made for freezing substances, such as ice cubes and thelike, and for cooling circulating air in the food storage compartmentwhereby. continuous refrigeration at substantially constantpredetermined temperatures is assured and the necessity of periodicinoperative conditions of the system for defrosting is avoided.

- Another object of my invention is the simplicity of parts and theirarrangement within the refrigerator cabinet whereby theaforesaid/objects ,may be economically and easily carried out.

Other objects and advantages will be apparent from the followingdescription, reference being I 40 had to the accompanying drawing.

In the drawing:

Fig. 1 is a vertical view, partly in cross section and partly inelevation, of a refrigerating apparatus embodying features of myinvention;

45 "Fig. 2 is a fragmentary view of the apparatus shown in Fig. 1, takenin the direction of arrows 2-2 in Fig.1;

'Fig. 3 is a vertical view in cross section of a control valve embodyingfeatures of'my inven- 3 tion; and

Fig. 4 is a view taken along the line 4-4 of Fig.3. Referring to-thedrawing, the numeral: 29 designates. in general, a cabinet having a comeMiami; 22 .for the storage of foods to be refrigerated, a freezingcompartment 23,. and a machine compartment 24. The cabinet isconstructed of insulating walls, including side walls 26, rear wall 21,front wall 28', bottom wall 29 and top wall 30. The cabinet alsoincludes a fixed, vertical insulating wall 32 which extends from therear wall 21 to the front wall 28 and from the top wall 30 to the bottomwall 29, separating the food compartment from the freezing compartment.An inner metallic lining. member 35 forms the inner walls of the foodcompartment and is, preferably, provided with a coating of vitreousenamel, such as porcelain, to provide a neat appearing compartment andone which may be easily cleaned. A similar inner metallic lining member31 forms the inner walls of the compartment 23. The liner 31 may becoated the sameas'liner 35. The front wall 28 is provided with anopening 38 through which access may be had to the food compartment 22.*The opening 38 is closed by door 40. A second opening may be providedin the front wall 28 in advance ofthe freezing compartment-23 forgaining access to the compartment 23. Any suitable door (not shown) maybe used for closing the latter open-+ ing in wall 28.

Within the freezing compartment 23 is disposed a refrigerant evaporator45 which is suspended from wall by brackets 41. The evaporator 45comprises, in general, a header 49 which has 30 a space within itsinterior for both liquid and gaseous refrigerants. v Dependingv upon theheader 49 are a plurality of conduits 50. -To the conduits 50 areattached a plurality of vertically spaced refrigerant containingshelves'il. The shelves 5i are provided for supporting icemakingreceptacles (not shown). Liquid refrigerant is delivered to theshelves 5| through conduits 50, which are in open communication on their7 upper ends with the header 49 and also in open communication with theinterior of each of the shelves 5|. Preferably, the shelves areconstructed of sheet metal plates suitably secured together byweldingbut spaced apart between the sheets of metal. By operating theevaporator 45 at sufliciently low enough temperatures and by supportingthe ice making receptacles on the upper surfaces of the refrigerantcontaining plates, the water in the receptacles will be rapidly frozen.If desired, desserts and the like may be placed in the receptaclesstored on the'shelves ll. Also. if desired, the frozen deserts and. thelike may be removed when frozen from the shelves andplaced on thetopofthe wall29ineompartmeat 23 immediately below'the evaporator 5 where thesubstances will be retained in a frozen condition, I

Within the food compartment 22 there is disposed a refrigerantevaporator 50. Evaporator 55 is of the plate type and is secured to thewall :2.

As willbe noted in the. drawing, the evaporator 55 extends over themajor portion of wall 02 within compartment '22. By providing anevaporator of this size and by solocating it in compartment 22, it ispossible to substitute for the insulated wall 32 a thin metallic wallsince the evaporator is arranged to prevent the transfer of heat fromthe compartment 22 into the com-' partment 23. Preferably, theevaporator 55 is constructed of sheet metal plates which are securedtogether about their peripheries thereof by seamwelding and welded atvarious points intermediate their edges but spaced apart between thewelded points to provide a space for refrigerant. In order to increasethe heat transfer characteristlcs of evaporator 55, Ihaveprovidedaplurality'of spaced parallel fins 51 on one 'side of theevaporator".

- A refrigerant condensing element 50 is disposed in the machinecompartment 24. This elementmay be supported in compartment 24 by anysuitable means (not shown). The elementinciudes a compressor 52, motor.53 for operating the compressor, condenser 65 and high side floatmechanism 51. The compressor 52 withdraws evaporated refrigerant fromthe evaporators 45 and 55 through a vapor-conduit 09, compresses theevaporated'refrigerant and delivers itto the condenser wherein it isliquefied and from which.

it is delivered to the high side float mechanism 61. Liquid refrigerantis delivered to the evaporators through liquid supply conduit 10 underthe control of float mechanism 51. l

.. Liquid refrigerant is first delivered to evaporator 55 through aconduit 10, and from the evaporator 55 liquid and gaseous. refrigerantis delivered to the evaporator 45 through conduit 12.

Evaporated refrigerant is withdrawn from the evaporator 45 through thevapor conduit 50.

Preferably, the condensing element is i'ntermit tently operated. Inorder-to control the operaorator 55. switches of this'type are well.known in the art and'further illustration thereof in the drawing isdeemed unnecessary. Thus, it will be noted that the operation of motor55"is controlled in response to changes in temperatures in either orboth of the evaporators. In view of the fact that the evaporators 45 and55 are of the T so-called flooded type, the temperatures therein beardirect relation to the pressure existing therein. I r

'. m order to maintain e predetermined tempereture differential betweenthe evaporators 45 and. 55 during operation of :the condensing element,I have provided a pressure responsive valve. I05

-which is interposed in the conduit 12 for controlling the flow ofliquid and gaseous refrigerant from,'the evaporator 55 to the evaporator45.

The pressure responsive valve I05 is adapted to maintain a.predetermined pressure di'iferential between the evaporators l5 and 45during operation of the condensing element'to thus maintain atemperature differential between said evaporators. As shown in Fig.3,,thepressure responsive valve includes a valve proper I01 and valveseat m located within a casing I00. The casing I00 is provided with aninlet l i0 to "which that portion of conduit 12 which extends betweenthe valve I05 and the outlet end of evaporator 55 is connected. Thevalve I05 is also provided with an outlet M2 to which theevaporator 45is connected by another portion of the'conduit 12. The valve proper I0!is secured to weight 5 which is adapted to move upwardly and downwardlywithin a chamber H6, depending upon the pre'ssure of the refrigerantexerted on valve proper 5 I01. Preferably, the chamber 1 l0 iscylindrical in shape and also, preferably. the weight H5 is providedwith a'plurality of arcuate portions Ill away flat portions HQ-betweenthe arcuate portions 0 to provide spaces between the walls of thechamber and the weight so as to prevent binding of theweight in thechamber, and also to prevent a. dash pot action therein. When thepressure of the refrigerant in the evaporator 55 reaches a predeterminedpoint, for example, equal to the pressure withinthe evaporator 45, and'is of sufllcient force to lift weight I I5 and the valve proper, theliquid and gaseous refrigerant will which conform to the contour of thewalls of. the v chamber. The weight is also provided with cut-,

move the valve I01 and weight 5 upwardly to 1 allow liquid and gaseousrefrigerant to enter the chamber H5, whence it passes through outlet H2inconduit 12 into-evaporator 45. When the pres- I sure recedes to apredetermined point, for ex-' ample, to a point less than it requires toopen valve J01, the weight and valve proper move downwardly to cause thevalve ,l01 to engageitself with seat 100 to prevent further passage ,ofrefrigerant into the evaporator 45. The

weighted valve is arrangedto .be intermittently,

operated so as t'o-m'aintain a predetermined pres- ,sure differentialbetween the evaporators 45 and 55. As previously stated-herein, thepressure differential is controlled by the weight of the weight-1 1 edvalve proper I01. In other words, before refrigerant may pass from theevaporator '55 to the evaporator, the pressure within the evaporator 55must be equal to the pressure in the evaporator 45, plus the amountequal to .move the weight tial is maintained during operation of thecone.

,densing element irrespective of the temperature ranges maintained inevaporators and H5 upwardly to remove the valve I01 from its seat I00.This predetermined pressure diiferen-;

i Preferably, the thermostatic switch is so that the evaporator will beoperated at temperatures which are slightly above that which would belikely to cause the collection of frost or ice thereon due to thedepositjof moisture, fromthe circulating air in the food compartment. Ifdesired, the thermostat may be set to operate evaporator" at atemperature which would allow a slight 111m of frost to collect thereonduring the on-phase of the refrigerating cycle and melted off during theoff-phase oi the refrigerating cycle. set so as to cause operation ofthe condensing eleevaporator 45 so that said evaporator will be freezingtherein. 7

In the refrigerating system herein described, I

Preferably, the thermostatic switch is is i 7 ment at predeterminedpressure limits within the operated at temperatures :'which cause'rapidoperation when thepressures within the evapo-.

prefer to use sulphur dioxide as a refrigerant. when sulphur dioxide isused as the refrigerant and when a predetermined setting of the switch11 is made, I have found that the cyclic operation of the system isbetween an upper and lower pressure range limit in the evaporator, whichlimits may be fourteen pounds pressure when the motor cuts in and fourpounds pressure of the.

refrigerant when the motor cuts out. By the use of the pressureresponsive valve I05 and by determining the weight member I I5 thereofso that a seven pound pressure differential is maintained between thetwo evaporators during the operating of the condensing element, I havefound that when the aforementioned pressure range limits exist in theevaporator 55 that the upper and lower pressure range limits existing inthe evaporator 45 extend between an upper limit of four pounds pressureof the refrigerant and lower limit of six inches of. vacuum. With suchpressure range limits existing in the evaporator 45, it

will be noted that the substances may be frozen rapidly.

Assuming that a large quantity of substances to be frozen should beapplied to the ice freezing evaporator 45, the pressure of therefrigerant in said evaporator is increased by the heat of thesubstances. Inasmuch as the thermostatic switch 11 is responsive tochanges in temperatures in the evaporator 55, it is necessary to providesome means .for immediately initiating operating of the condensingelement 50 when a large quantity of substances to be frozen is appliedto the evaporator 45 so that the heat absorbed by the refrigerant in theevaporator 45 may be immediately withdrawn to start .the process offreez- For this reason, the

ing the said substances. thermostatic switch 15 has been provided.Preferably, the switch 15 is arranged so that it cuts in the motor 63when the pressure of the refrigerant inthe evaporator 45 reaches anupper limit of slightly above four pounds pressure and cuts out themotor 63 when the pressure of the refrigerant falls to six inches ofvacuum. Thus, it will be noted that when the pressure in the evaporator45 exceeds four pounds, the condensing element begins operation toreducethe pressure within the evaporator 45. Preferably, the switches 15 and11 are connected in parallel 'so that the switch 'I'l will control theoperation of the condensing element to maintain the desired tem-'taining the temperatures withinthe food storage compartment 22 withinpredetermined range limits, by simply controlling the operation of thecondensing element by means of a thermostatic switch "I 'However, inorder to control the operation of the condensing element so that ice mayreadily be frozen in thecompartment 23, I have,

provided the thermostatic switch I5 which immediately cuts themotor-compressor unit into rat'or 45 rise to slightly above four poundsirrespective of the pressures existing in evaporator v55. Thus, it willbe noted that the pressure responsive switch I5 is included forpromoting rapid ice freezing.

Although I have described my pressure differential valve H15 inconnection with an interreadily be apparent from the foregoing that saidvalve may be used advantageously in a continuously operated system'whereit would maintain a predetermined pressure differential between theevaporators 45 and 55 at all times.

From the foregoing, it will be noted that I have provided an improvedand simple arrangement for maintaining a pressure differential between anumber of different evaporators and for maintaining a* temperaturedifferential therebetween. It will also be noted that the pressuredifferential is obtained automatically as the pressures in theevaporators are being reduced by the condensing element. In addition, itwill be noted that said predetermined pressure differential ismaintained irrespective of the setting mittently operated refrigeratingsystem, it will,

immediately upon entrance of the liquid refrigerant into the supplyconduit I0 after leaving the high side float mechanism 61, I haveprovided a pressure responsive valve, designated by the numeral I20.This valve is interposedin the conduit I0 adjacent the inlet of theevaporator 55. Thisvalve maintains the pressures in the supply conduit10 sufficiently high enough so as to prevent refrigeration taking placein said conduit so that no refrigeration takes place before entering theevaporator 55. This prevents loss of refrigeration, increases thecapacity of the apparatus and prevents the collection of moisture in theinsulated portions of the food storage compartment through which theliquid supply- ,conduit 10 extends.

Preferably, the valve I20 is of the same construction as the valve I05,with the'weighted member H5 being of different size so as to maintainthe pressure of refrigerant within the conduit 10 above that which wouldcause the collection of frost on the conduit I0. Thus, it will be notedthat within the refrigerating system described herein, there are fourportions thereof in which the pressures arev different. For instance, arelatively high pressure within the condenser 55, the pressure in theconduit 10 h which is somewhat belowthe pressure existing in thecondenser and above the pressure existing in the evaporator 55, and arelatively low pressure which exists in the evaporator 45.

Although only a preferred formof the invention has been illustrated, andthat form de-, scribed in detail, itwill-be apparent to' those skilledin the art thatvarious modifications may be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims.

What I claim as my invention is: 1. A refrigerating system comprising arefrigerant condensing element, ,a number of different refrigerantevaporators connected in series,-

means connected in said system for maintaining a predeterminedtemperature differential between the different'evaporators during theoperation of said condensing element, and means associated with eachevaporator for controllingthe operation of said condensing element.

' 2. A refrigerating'system comprising a refrigerant condensing element,a low temperature refrigerant evaporator, a relatively high'temperaturerefrigerant evaporator, control means responsive to changes inconditions within said relatively high temperature-evaporator forinitiat-- lnlr'operation of said condensing element when thetemperatureof the refrigerant in said relatively high a temperatureevaporator attains a certain high value; and for interrupting, theoper-z 5' ationof said element when said temperature'is ential, and theother temperature responsive means being operable onlyin the event of apre-' reduced toacertain low value, auxiliary control.

means for controllingoperation of said condens- Y ing element only inthe event the temperature in said lqw temperature evaporator exceeds theperature responsive means for controlling the 0 operation of saidcondensing element, one of said temperature responsive means beingoperable to normally control the operation of the condensing element tomaintain said temperature dinerdetermined demand for refrigeration byone of said evaporators to'control the operation of said I condensingelement to thereby insure'maintainso in: said substantially'constanttemperature differential atalltimes.

v 4. A refrigerating system comprising a number of different refrigerantevaporating elements;

means for/ simultaneously reducing the pressures in said elements,temperature differential means 35 for maintaining a predeterminedtemperature differential between said elements, control means normallycontrolling the operation of the means for reducing said pressures, andauxiliary control means arranged to be effective to control 9 theoperation of said pressure-'reducing-means in the event the temperaturesin one of said evaporators isincreased toa certainamount.

. temperature evaporator, a relatively high temevaporator, pressurereducing means for controlling the flow of liquid and gaseous trollingthe operation of saidcondensing element.

associated with s'aid'evaporators, means for main:

taining a predetermined pressure diiferential between said evaporatorsduring operation of said pressure reducing means, and means directlyassociated with said low temperature evaporator ,5

for controlling the operation of said pressurereducing means. v i

6. A refrigerating system comprising a low temperature evaporator,a--relative1y high temperature evaporator, pressurereducing means as- 10sociated with said evaporators, meansfor maintaining a predeterminedpressure differential between saidevaporatorsduring operation of saidpressure reducing means to maintains. predetermined temperaturedifferential between said evaporators, and independent means directlyassociated with eachevaporator for controlling the operation of saidpressure reducing means; 7. Arefrigerating system'comprising arefrigerant condensing element, a refrigerant evapolater, a secondrefrigerant evaporator connected in series with the first namedevaporator, a pressure responsive valve connected in said systemrefrigerant from the first evaporator'to the sec- 'ond to maintain apredetermined temperature differential between said evaporators duringthe operation of said condensingelement, and means associated with eachof said evaporators for con- 8: A refrigerating system comprising arefrigerant condensing element, a. refrigerant evaporator a secondrefrigerant evaporator connected in series with the first namedevaporator, a pres I sureresponsive valve connected in said system forcontrolling the flow of liquid and gaseous refrigerant from the firstevaporatorto the sec-'- ond' to maintain a predetermined temperaturedifierential between said evaporators during the operation of saidcondensing element, and thermostatic means directly associatedwith eachof I said evaporators for controlling the operation -5. A refrigeratingsystem comprising a low of said condensing element.

